The Supreme Court in 2007 declared that carbon dioxide and other “heat-trapping gases to be pollutants that endanger public health and welfare.” That ruling set the Environmental Protection Agency (EPA) in motion to establish regulations to control the gases. A New York Times article quoted the EPA as saying the science supporting the endangerment finding “compelling and overwhelming.” They proposed a law under the Clean Air Act to regulate “heat-trapping gases” (which includes methane, nitrous oxide, and hydroflurocarbons in addition to carbon dioxide). It is odd that the EPA has a paper that presents a solid argument that much of the carbon dioxide in the atmosphere is the result of natural conditions separate from the activities of man. The paper first observes that the climate of the earth has changed throughout history preceding and following the arrival of man. Various scientific studies show that temperatures and carbon dioxide levels have been higher than present levels for about two-thirds of the last 400 million years. The causes of climate change are listed as:

• Changes in the Earth’s orbit and tilt affect the amount of sunlight received on the surface of the planet
• Changes in the intensity of the sun is an obvious cause of changes in temperature, and the NASA believes reduced solar activity was the cause of the “Little Ice Age” from the 1400s to 1700s
• Volcanic aerosols block sunlight; the Tambora Volcano in Indonesia in 1815 lowered global temperatures by as much as five degrees Fahrenheit and caused 1816 to be “the year without a summer in New England 1816
• Volcanic eruptions release carbon dioxide

I find the most interesting part of the paper to be a discussion under the bullet titled “Changes in greenhouse gas concentrations.” “The heating or cooling of the Earth’s surface can cause changes in greenhouse gas concentrations. For example, when global temperatures become warmer, carbon dioxide is released from the oceans. When changes in the Earth’s orbit trigger a warm (or interglacial) period, increasing concentrations may amplify the warming by enhancing the greenhouse effect. When temperatures become cooler, CO2 enters the ocean and contributes to additional cooling. During at least the last 650,000 years…during warm interglacial periods CO2 levels have been high and during cool glacial periods, CO2 levels have been low.” (Emphasis added) It is thus quite clear that those who blame changes in temperature on changes in carbon dioxide concentrations have ignored that the reverse is true.

I often read that Arctic sea ice coverage is continuing to shrink. I frequently look at the National Snow and Ice Data Center graphs of Arctic sea ice extent, and it is true that current coverage is less than the 1979-2000 average. However, the 2011 data is virtually tracking the 2007 levels (The amounts in April 2011 were higher than April 2007, but June 2011 levels are slightly lower than June 2007). How is it possible for no ice loss since 2007 translate to “continuing to shrink?” Current news reports are once again talking about severe and hot weather are being caused by global warming. The EPA paper describing the causes of past climate change would say that man has little influence on what may or may not happen.